Wave pressure variations around a large cylinder due to wavecurrent interactions has been investigated experimentally in constant and varying water depth. Various experimental conditions were achieved through combinations of incident wave, current velocities, and different intersection angels between waves and current. The time histories of the dynamic pressure on the cylinder were measured and analyzed. Comparison of the pressure distributions around the cylinder in water of constant and varying depth was made. The wave pressure variations for constant and varying water depth have the same trend. Nevertheless, due to the effect of shoaling, the wave pressures around the cylinder in varying depth are larger than that in water of constant depth.
In the recent years, utilization of ocean space such as offshore industrial estate, land reclamation, man-made island and offshore structures are intensively undergoing. In order to ensure the safety of the ocean structures, understanding of ocean properties must be conducted. For problems such as the combined effect of wave, currents and varying topography, Jonsson et al. (1970) investigated the interactions between wave and current on slowly varying topography. Based on mild slope equation derived by Berkhoff (1972) and by using finite difference method, Booij (1981) investigated the wave-current interaction phenomena. Liu (1983) also extended the mild slope equation to include the effects of currents, and using hybrid finite element method to calculated the wave-current and offshore structure interaction. By using WKB perturbation technique and Lagrangian theory, the works of Booij and Liu were further revised by Kirby (1984). Lin and Hsu (1991) proposed a numerical model with the mild slope equation derived by Kirby (1984), where the interaction of wave refraction-diffraction and currents problems were solved with finite/boundary element method. Lin et al. (1994) conducted model experiments to verify the numerical model proposed by Lin and Hsu.